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Family: Gentoo Local Security Checks --> Category: infos
[GLSA-200402-02] XFree86 Font Information File Buffer Overflow Vulnerability Scan
Vulnerability Scan Summary
XFree86 Font Information File Buffer Overflow
Detailed Explanation for this Vulnerability Test
The remote host is affected by the vulnerability described in GLSA-200402-02
(XFree86 Font Information File Buffer Overflow)
Exploitation of a buffer overflow in The XFree86 Window System
discovered by iDefence allows local attackers to gain root
rights.
The problem exists in the parsing of the 'font.alias' file. The X
server (running as root) fails to check the length of the user
provided input, so a malicious user may craft a malformed
'font.alias' file causing a buffer overflow upon parsing,
eventually leading to the execution of arbitrary code.
To reproduce the overflow on the command line one can run:
# cat > fonts.dir <
1
word.bdf -misc-fixed-medium-r-semicondensed--13-120-75-75-c-60-iso8859-1
EOF
# perl -e 'print "0" x 1024 . "A" x 96 . "\n"' > fonts.alias
# X :0 -fp $PWD
{Some output removed}... Server aborting... Segmentation fault (core dumped)
Impact
Successful exploitation can lead to a root compromise provided
that the attacker is able to execute commands in the X11
subsystem. This can be done either by having console access to the
target or through a remote exploit against any X client program
such as a web-browser, mail-reader or game.
Workaround
No immediate workaround is available
a software upgrade is required.
Gentoo has released XFree 4.2.1-r3, 4.3.0-r4 and 4.3.99.902-r1 and
encourages all users to upgrade their XFree86
installations. Vulnerable versions are no longer available in
Portage.
References:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-0083
http://www.idefense.com/application/poi/display?id=72&type=vulnerabilities
Solution:
All users are recommended to upgrade their XFree86 installation:
# emerge sync
# emerge -pv x11-base/xfree
# emerge x11-base/xfree
Threat Level: High
Click HERE for more information and discussions on this network vulnerability scan.
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